Which detector did you use? FID?
I suggest you raise the temperature to the maximal allowable value (300
Celsius degree? check the manu if you have one) for at least half hour. It
will burn out all residuals left in your old GC detector.
You can also dissemble the detector to clean every part before you run the
temperature.
You should do the same for the injector before you run sample.
The worse scenario would be a default electronic part in the circuitry. Then
you would have to find a professio
